It is proposed to use X-ray and neutron diffraction single crystal investigations in conjunction with interactive computer graphics and ab-initio quantum mechanical calculations to study the following problems in carbohydrate chemistry: (1)To compare experimentally the electron density distributions at anomeric and non-anomeric carbon centers in a simple carbohydrate molecule and to correlate these results with the theoretical predictions from ab-initio quantum mechanical calculations, (2)To seek relationships governing the hydrogen-bond structural patterns in carbohydrate crystal structures, (3)To seek to distinguish between the effects of intra- and intermolecular forces in determining the deviations from ideal chair conformations in pyranose sugar molecules in the crystalline state using the methods of molecular mechanics.